Adding flavoring agents to secondary fermentation

[zhooker]

Boil Volume: 0.90gal
Batch Volume: 0.78gal
1# Light DME
.3oz Cascade 60min
.125oz Columbus 60min
.125oz Amarillo 30min
.125oz Amarillo 15min
.2oz Cascade (Dry hop in secondary fermentation)

This was a small batch to clean out my leftover ingredients. As you can see, only brewing about a six-pack's worth. The aim was a massively hopped but mid-level ABV. Thinking I will come out around 110 IBU and 5.5% ABV.

I am about to rack to secondary, which will last for about 2 weeks. I am dumping in those remaining Cascade hops. However, I would also like to add one or two other flavoring agents, just to play around.

So -- given this brew profile, WHAT flavoring agents would you recommend adding to the beer, and HOW should they be added?

Also -- will I need to add sugar or yeast to the secondary? Will I need to prime when I bottle this?

THANKS!